Electroforming is a technique used to make intricate precision structures that are difficult to fabricate by other processes, such as machining. Useful devices, such as wave guides and printing screens, have been made by electroplating onto a preformed shape and subsequently selectively removing the shaped structure or mandrel to leave a free standing part made from the electroplated metal. When good corrosion properties are required, nickel works very well as the electroplated metal.
Drop generators for full page width print heads of 8.5 inches or more are difficult to fabricate by ordinary machining methods. As shown in Wood U.S. Pat. No. 4,999,647, the preferred drop generator shape is long and narrow. The channel for ink delivery has a specific and well defined geometry, as shown in FIG. 2 in Wood U.S. Pat. No. 4,999,647. The cylindrical channel and connecting slot are typically made by gun drilling, electric discharge machining, and grinding. Even with great care, skilled machinists find it difficult and time consuming to make these parts to the exacting tolerance required.
Other solutions simplifying fabrication of internal passages include symmetrically dividing the drop generator into two machined halves and then brazing these two together to make the whole part. This solution cannot be done with long narrow drop generators due to warping that occurs from exposure to high brazing temperatures.
A need exists for a method to fabricate reproducibly the internal cavities of the drop generator smoothly and without irregularities that normally occur in machining.
The present embodiments meet this need.